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-rw-r--r--erts/emulator/sys/unix/sys_time.c16
-rw-r--r--erts/include/internal/ethread.h50
-rw-r--r--erts/lib_src/common/ethr_aux.c29
3 files changed, 69 insertions, 26 deletions
diff --git a/erts/emulator/sys/unix/sys_time.c b/erts/emulator/sys/unix/sys_time.c
index 9738a8c352..03d39c7ce6 100644
--- a/erts/emulator/sys/unix/sys_time.c
+++ b/erts/emulator/sys/unix/sys_time.c
@@ -971,18 +971,18 @@ static ErtsSysPerfCounter calculate_perf_counter_unit(void) {
static int have_rdtscp(void)
{
#if defined(ETHR_X86_RUNTIME_CONF__)
- /* On early x86 cpu's the tsc varies with
- the current speed of the cpu, which means that the time per
- tick vary depending on the current load of the cpu. We do not
- want this as it would give very scewed numbers when the cpu is
- mostly idle.
- If we have the rdtscp feature it is a sign that the cpu is
- relatively modern, and thus the tsc quite stable so we use it then.
+ /* On early x86 cpu's the tsc varies with the current speed of the cpu,
+ which means that the time per tick vary depending on the current
+ load of the cpu. We do not want this as it would give very scewed
+ numbers when the cpu is mostly idle.
+ The linux kernel seems to think that checking for constant and
+ reliable is enough to trust the counter so we do the same.
If this test is not good enough, I don't know what we'll do.
Maybe fallback on erts_sys_hrtime always, but that would be a shame as
rdtsc is about 3 times faster than hrtime... */
- return ETHR_X86_RUNTIME_CONF_HAVE_RDTSCP__;
+ return ETHR_X86_RUNTIME_CONF_HAVE_CONSTANT_TSC__ &&
+ ETHR_X86_RUNTIME_CONF_HAVE_TSC_RELIABLE__;
#else
return 0;
#endif
diff --git a/erts/include/internal/ethread.h b/erts/include/internal/ethread.h
index 9956473057..e5c5cdfa33 100644
--- a/erts/include/internal/ethread.h
+++ b/erts/include/internal/ethread.h
@@ -274,18 +274,40 @@ ETHR_PROTO_NORETURN__ ethr_fatal_error__(const char *file,
|| (defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64))))
# define ETHR_X86_RUNTIME_CONF__
-# define ETHR_X86_RUNTIME_CONF_HAVE_DW_CMPXCHG__ \
- (__builtin_expect(ethr_runtime__.conf.have_dw_cmpxchg != 0, 1))
-# define ETHR_X86_RUNTIME_CONF_HAVE_NO_DW_CMPXCHG__ \
- (__builtin_expect(ethr_runtime__.conf.have_dw_cmpxchg == 0, 0))
-# define ETHR_X86_RUNTIME_CONF_HAVE_SSE2__ \
- (__builtin_expect(ethr_runtime__.conf.have_sse2 != 0, 1))
-# define ETHR_X86_RUNTIME_CONF_HAVE_NO_SSE2__ \
- (__builtin_expect(ethr_runtime__.conf.have_sse2 == 0, 0))
-# define ETHR_X86_RUNTIME_CONF_HAVE_RDTSCP__ \
- (__builtin_expect(ethr_runtime__.conf.have_rdtscp != 0, 1))
-# define ETHR_X86_RUNTIME_CONF_HAVE_NO_RDTSCP__ \
- (__builtin_expect(ethr_runtime__.conf.have_rdtscp == 0, 0))
+# define ETHR_X86_RUNTIME_CONF_HAVE_META(feature) \
+ (__builtin_expect(ethr_runtime__.conf.have_##feature != 0, 1))
+# define ETHR_X86_RUNTIME_CONF_HAVE_NO_META(feature) \
+ (__builtin_expect(ethr_runtime__.conf.have_##feature == 0, 0))
+
+# define ETHR_X86_RUNTIME_CONF_HAVE_DW_CMPXCHG__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_META(dw_cmpxchg)
+# define ETHR_X86_RUNTIME_CONF_HAVE_NO_DW_CMPXCHG__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_NO_META(dw_cmpxchg)
+# define ETHR_X86_RUNTIME_CONF_HAVE_SSE2__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_META(sse2)
+# define ETHR_X86_RUNTIME_CONF_HAVE_NO_SSE2__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_NO_META(sse2)
+# define ETHR_X86_RUNTIME_CONF_HAVE_RDTSCP__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_META(rdtscp)
+# define ETHR_X86_RUNTIME_CONF_HAVE_NO_RDTSCP__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_NO_META(rdtscp)
+# define ETHR_X86_RUNTIME_CONF_HAVE_CONSTANT_TSC__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_META(constant_tsc)
+# define ETHR_X86_RUNTIME_CONF_HAVE_NO_CONSTANT_TSC__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_NO_META(nonstop_tsc)
+# define ETHR_X86_RUNTIME_CONF_HAVE_NONSTOP_TSC__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_META(nonstop_tsc)
+# define ETHR_X86_RUNTIME_CONF_HAVE_NO_NONSTOP_TSC__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_NO_META(nonstop_tsc)
+# define ETHR_X86_RUNTIME_CONF_HAVE_TSC_RELIABLE__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_META(tsc_reliable)
+# define ETHR_X86_RUNTIME_CONF_HAVE_NO_TSC_RELIABLE_TSC__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_NO_META(tsc_reliable)
+# define ETHR_X86_RUNTIME_CONF_HAVE_NONSTOP_TSC_S3__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_META(nonstop_tsc_s3)
+# define ETHR_X86_RUNTIME_CONF_HAVE_NO_NONSTOP_TSC_S3__ \
+ ETHR_X86_RUNTIME_CONF_HAVE_NO_META(nonstop_tsc_s3)
+
#endif
#if (defined(__GNUC__) \
@@ -305,6 +327,10 @@ typedef struct {
int have_dw_cmpxchg;
int have_sse2;
int have_rdtscp;
+ int have_constant_tsc;
+ int have_tsc_reliable;
+ int have_nonstop_tsc;
+ int have_nonstop_tsc_s3;
#endif
#if defined(ETHR_PPC_RUNTIME_CONF__)
int have_lwsync;
diff --git a/erts/lib_src/common/ethr_aux.c b/erts/lib_src/common/ethr_aux.c
index fbd870c2b5..3e7aad16c7 100644
--- a/erts/lib_src/common/ethr_aux.c
+++ b/erts/lib_src/common/ethr_aux.c
@@ -144,16 +144,33 @@ x86_init(void)
eax = 0x80000000;
ethr_x86_cpuid__(&eax, &ebx, &ecx, &edx);
- if (eax >= 0x80000001) {
- /* Get the extended feature set */
- eax = 0x80000001;
+ if (eax < 0x80000001)
+ return;
+
+ if (eax >= 0x80000007) {
+ /* Advanced Power Management Information */
+ eax = 0x80000007;
ethr_x86_cpuid__(&eax, &ebx, &ecx, &edx);
- } else {
- eax = ebx = ecx = edx = 0;
+
+ /* I got the values below from:
+ http://lxr.free-electrons.com/source/arch/x86/include/asm/cpufeature.h
+ They can be gotten from the intel/amd manual as well.
+ */
+
+ ethr_runtime__.conf.have_constant_tsc = (edx & (1 << 8));
+ ethr_runtime__.conf.have_tsc_reliable = (edx & (1 << 23));
+ ethr_runtime__.conf.have_nonstop_tsc = (edx & (1 << 24));
+ ethr_runtime__.conf.have_nonstop_tsc_s3 = (edx & (1 << 30));
+
}
-
+
+ /* Extended Processor Info and Feature Bits */
+ eax = 0x80000001;
+ ethr_x86_cpuid__(&eax, &ebx, &ecx, &edx);
+
/* bit 27 of edx is set if we have rdtscp */
ethr_runtime__.conf.have_rdtscp = (edx & (1 << 27));
+
}
#endif /* ETHR_X86_RUNTIME_CONF__ */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-26 01:05:11 +0000